add operator to convert vector to symmetric matrix and back

8 files changed, 150 insertions, 0 deletions

diff --git a/polymatrix/expression/fromsymmetricmatrixexpr.py b/polymatrix/expression/fromsymmetricmatrixexpr.py
new file mode 100644
index 0000000..8ddf2ef
--- /dev/null
+++ b/polymatrix/expression/fromsymmetricmatrixexpr.py
@@ -0,0 +1,4 @@
+from polymatrix.expression.mixins.fromsymmetricmatrixexprmixin import FromSymmetricMatrixExprMixin 
+
+class FromSymmetricMatrixExpr(FromSymmetricMatrixExprMixin):
+	pass
diff --git a/polymatrix/expression/impl/fromsymmetricmatrixexprimpl.py b/polymatrix/expression/impl/fromsymmetricmatrixexprimpl.py
new file mode 100644
index 0000000..1c54162
--- /dev/null
+++ b/polymatrix/expression/impl/fromsymmetricmatrixexprimpl.py
@@ -0,0 +1,8 @@
+import dataclass_abc
+from polymatrix.expression.fromsymmetricmatrixexpr import FromSymmetricMatrixExpr 
+
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin 
+
+@dataclass_abc.dataclass_abc(frozen=True)
+class FromSymmetricMatrixExprImpl(FromSymmetricMatrixExpr):
+	underlying: ExpressionBaseMixin
diff --git a/polymatrix/expression/impl/tosymmetricmatrixexprimpl.py b/polymatrix/expression/impl/tosymmetricmatrixexprimpl.py
new file mode 100644
index 0000000..da43157
--- /dev/null
+++ b/polymatrix/expression/impl/tosymmetricmatrixexprimpl.py
@@ -0,0 +1,8 @@
+import dataclass_abc
+from polymatrix.expression.tosymmetricmatrixexpr import ToSymmetricMatrixExpr 
+
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin 
+
+@dataclass_abc.dataclass_abc(frozen=True)
+class ToSymmetricMatrixExprImpl(ToSymmetricMatrixExpr):
+	underlying: ExpressionBaseMixin
diff --git a/polymatrix/expression/init/initfromsymmetricmatrixexpr.py b/polymatrix/expression/init/initfromsymmetricmatrixexpr.py
new file mode 100644
index 0000000..3af7dc3
--- /dev/null
+++ b/polymatrix/expression/init/initfromsymmetricmatrixexpr.py
@@ -0,0 +1,10 @@
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expression.impl.fromsymmetricmatrixexprimpl import FromSymmetricMatrixExprImpl
+
+
+def init_from_symmetric_matrix_expr(
+		underlying: ExpressionBaseMixin,
+):
+	return FromSymmetricMatrixExprImpl(
+		underlying=underlying,
+)
diff --git a/polymatrix/expression/init/inittosymmetricmatrixexpr.py b/polymatrix/expression/init/inittosymmetricmatrixexpr.py
new file mode 100644
index 0000000..89fc46c
--- /dev/null
+++ b/polymatrix/expression/init/inittosymmetricmatrixexpr.py
@@ -0,0 +1,10 @@
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expression.impl.tosymmetricmatrixexprimpl import ToSymmetricMatrixExprImpl
+
+
+def init_to_symmetric_matrix_expr(
+		underlying: ExpressionBaseMixin,
+):
+	return ToSymmetricMatrixExprImpl(
+		underlying=underlying,
+)
diff --git a/polymatrix/expression/mixins/fromsymmetricmatrixexprmixin.py b/polymatrix/expression/mixins/fromsymmetricmatrixexprmixin.py
new file mode 100644
index 0000000..906adf8
--- /dev/null
+++ b/polymatrix/expression/mixins/fromsymmetricmatrixexprmixin.py
@@ -0,0 +1,44 @@
+
+import abc
+import dataclasses
+import math
+from polymatrix.expression.utils.getvariableindices import get_variable_indices_from_variable
+
+from polymatrix.polymatrix.init.initpolymatrix import init_poly_matrix
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expressionstate.mixins.expressionstatemixin import ExpressionStateMixin
+from polymatrix.polymatrix.mixins.polymatrixmixin import PolyMatrixMixin
+
+
+class FromSymmetricMatrixExprMixin(ExpressionBaseMixin):
+    @property
+    @abc.abstractclassmethod
+    def underlying(self) -> ExpressionBaseMixin:
+        ...
+
+    # overwrites abstract method of `ExpressionBaseMixin`
+    def apply(
+        self, 
+        state: ExpressionStateMixin,
+    ) -> tuple[ExpressionStateMixin, PolyMatrixMixin]:
+
+        state, underlying = self.underlying.apply(state)
+
+        assert underlying.shape[0] == underlying.shape[1]
+
+        terms = {}
+        var_index = 0
+
+        for row in range(underlying.shape[0]):
+            for col in range(row, underlying.shape[1]):
+                
+                terms[var_index, 0] = underlying.get_poly(row, col)
+
+                var_index += 1
+
+        poly_matrix = init_poly_matrix(
+            terms=terms,
+            shape=(var_index, 1),
+        )
+
+        return state, poly_matrix
\ No newline at end of file
diff --git a/polymatrix/expression/mixins/tosymmetricmatrixexprmixin.py b/polymatrix/expression/mixins/tosymmetricmatrixexprmixin.py
new file mode 100644
index 0000000..0d8c6ed
--- /dev/null
+++ b/polymatrix/expression/mixins/tosymmetricmatrixexprmixin.py
@@ -0,0 +1,62 @@
+
+import abc
+
+from polymatrix.expression.utils.getvariableindices import get_variable_indices_from_variable
+from polymatrix.polymatrix.init.initpolymatrix import init_poly_matrix
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expressionstate.mixins.expressionstatemixin import ExpressionStateMixin
+from polymatrix.polymatrix.mixins.polymatrixmixin import PolyMatrixMixin
+
+
+class ToSymmetricMatrixExprMixin(ExpressionBaseMixin):
+    @property
+    @abc.abstractclassmethod
+    def underlying(self) -> ExpressionBaseMixin:
+        ...
+
+    # overwrites abstract method of `ExpressionBaseMixin`
+    def apply(
+        self, 
+        state: ExpressionStateMixin,
+    ) -> tuple[ExpressionStateMixin, PolyMatrixMixin]:
+
+        state, underlying = self.underlying.apply(state)
+
+        assert underlying.shape[1] == 1
+
+        # state, variable_indices = get_variable_indices_from_variable(state, self.underlying)
+
+        def invert_binomial_coefficient(val):
+            idx = 1
+            sum_val = 1
+
+            while sum_val < val:
+                idx += 1
+                sum_val += idx
+
+            assert sum_val == val, f'{sum_val=}, {val=}'
+
+            return idx
+
+        # n_row = invert_binomial_coefficient(len(variable_indices))
+        n_row = invert_binomial_coefficient(underlying.shape[0])
+
+        terms = {}
+        var_index = 0
+
+        for row in range(n_row):
+            for col in range(row, n_row):
+                # terms[row, col] = {((variable_indices[var_index], 1),): 1.0}
+                terms[row, col] = underlying.get_poly(var_index, 0)
+
+                if row != col:
+                    terms[col, row] = terms[row, col]
+
+                var_index += 1
+
+        poly_matrix = init_poly_matrix(
+            terms=terms,
+            shape=(n_row, n_row),
+        )
+
+        return state, poly_matrix
diff --git a/polymatrix/expression/tosymmetricmatrixexpr.py b/polymatrix/expression/tosymmetricmatrixexpr.py
new file mode 100644
index 0000000..119e13b
--- /dev/null
+++ b/polymatrix/expression/tosymmetricmatrixexpr.py
@@ -0,0 +1,4 @@
+from polymatrix.expression.mixins.tosymmetricmatrixexprmixin import ToSymmetricMatrixExprMixin 
+
+class ToSymmetricMatrixExpr(ToSymmetricMatrixExprMixin):
+	pass